import cv2
import matplotlib.pyplot as plt

img = cv2.imread('apricot blossom.jpg',cv2.IMREAD_GRAYSCALE)

#Sobel算子
sobelx = cv2.Sobel(img,cv2.CV_64F,1,0,ksize=3)
sobely = cv2.Sobel(img,cv2.CV_64F,0,1,ksize=3)
sobelx = cv2.convertScaleAbs(sobelx)
sobely = cv2.convertScaleAbs(sobely)
sobelxy =  cv2.addWeighted(sobelx,0.5,sobely,0.5,0)

#Scharr算子
scharrx = cv2.Scharr(img,cv2.CV_64F,1,0)
scharry = cv2.Scharr(img,cv2.CV_64F,0,1)
scharrx = cv2.convertScaleAbs(scharrx) #先计算x方向梯度
scharry = cv2.convertScaleAbs(scharry) #再计算y方向梯度
scharrxy =  cv2.addWeighted(scharrx,0.5,scharry,0.5,0) #加权求和

#laplacian算子
laplacian = cv2.Laplacian(img,cv2.CV_64F)
laplacian = cv2.convertScaleAbs(laplacian)

plt.figure(figsize=(14,6),dpi=120)
plt.subplot(131)
plt.imshow(sobelxy,cmap='gray')
plt.title('Sobel')
plt.xticks([]),plt.yticks([])

plt.subplot(132)
plt.imshow(scharrxy,cmap='gray')
plt.title('Scharr')

plt.subplot(133)
plt.imshow(laplacian,cmap='gray')
plt.title('laplacian')
plt.xticks([]),plt.yticks([])

plt.show()
